These normally nocturnal birds forage for insects in the leaf litter on a forest floor. Normally. But the onset of one of the most severe droughts on record has set off the collapse of a line of ecological dominoes. Low rain begets low soil moisture, which begets lower plant growth and harder soils, which beget less food for insects and more inaccessible insects, which means less food for kiwi, which means more excursions by kiwi into the unsafe light of day and potentially higher mortality.

This game of ecological dominoes, triggered by water shortfalls, is seen the world over.

The seasonal swing to dry conditions in the Florida Everglades concentrates fish and other aquatic critters into ever smaller pools of water. These pools become the fast food joints of the bird world, and of bird watchers. The same applies to watering holes from Africa to Australia.

But while this seasonal swing is par for the course in Florida, a sustained climatic shift in the US Southwest that started in the 1970s caused several common animal species to go locally extinct, and some rare species to increase. The middle man in this case was the expansion of shrubs that fared better in the wetter winters. Shrubs have deeper roots than herbaceous plants, giving them a competitive advantage when more water infiltrates deeper into the soil, as would occur during wetter winters.

Back to kiwi, drought is not the number one threat – that dishonour goes to introduced mammals. But I imagine that the threats posed by drought would be substantially alleviated in predator-proof sanctuaries, where daylight foraging is less risky.

When it comes to Canterbury water governance, the balance of satisfaction has shifted dramatically over the last few weeks. Some are happier now that government-appointed commissioners will replace elected councilors at ECan. Some are not. And those who are not are increasingly making themselves heard.

At two meetings recently the malcontents voiced their feelings, from calm criticism to vociferous outrage. Running through both events were the feelings of eroded trust, lost democracy and endangered water. There is no way I can relay every nugget of observation, partly because I wasn’t omnipresent. But in the interests of shedding some light on the cogs between water and society, here are a few.

First, from Wednesday night:

â€¢ Yani Johanson, Christchurch City Councilor, reiterated the remark that Christchurch City Mayor, Bob Parker, did not consult with the city council on ECan’s performance. Indeed, there appeared to be substantial tension between Mayor and Council.

â€¢ Eugenie Sage, ECan councilor, remarked that there has been tension between ECan and the territorial authorities because of ECan’s demands regarding storm water and sewage operations.

â€¢ The lone Mayor to join the panel, Garry Jackson of Hurunui District, received a lot of harsh questioning but also a lot of applause for having the guts to show up.

â€¢ And on a social analysis of the attendees, the dominant hair colour was silver, and many heard about the event from a Green Party email. It was a Green Party event after all. A couple hundred were in attendance, inside out out, with a passers-by stopping to listen.

Turning to the Thursday night meeting, this one was about what people can do from here. Held in the Arts Centre’s Great Hall, the meeting was an ideas fest. Direct action was a common theme. Here are some of the ideas put forward:

â€¢ David Moorhouse, Christchurch Green Party, advocated a “rates resistance” or rates revolt. The rationale being “no taxation without representation.”

â€¢ The Melvin Hills Protection Society suggests a hikoi, starting at rivers on either end of Canterbury to converge on Christchurch’s main square.

â€¢ Brendan Burns, Labour MP, presented a petition to the House of Representatives.

â€¢ Polly Miller, President of Whitewater NZ, offered to give the in-coming commissioners a whitewater tour of the Hurunui River. This was perhaps the suggestion with the most potential for influence water governance before the next elections.

â€¢ Cantabrian artist Sam Mahon suggested both a black-clad candle-light vigil in the square, and monkey-wrenching of possible dams.

â€¢ And on the audience, it seemed a bit more youthful than the previous night – mostly middle-aged this time – but there was also a significant 20-something turnout. Probably about 200 came.

After much mulling, distilling and filtering, Crikey Creek is introducing another new series: Horton’s Index.

Many readers will know the name Horton. Not the one who heard a who, but Robert E. Horton – hydrologist extraordinaire. Horton was instrumental in the 20th century quantitative revolution in hydrology. He even got his name attached to one of the water cycle’s cogs – Hortonian overland flow.

Many readers, I’d like to think, also know of a certain Index – Harper’s Index. This index is a monthly index of ironic and often-pointedly political factoids, with numbers as the punch-lines. They can be funny, surprising and blunt. Numbers are good that way. No doubt that’s why Peter Gleick, water resources expert at the Pacific Institute, chose as a theme to his blog “Water by Numbers”.

With the above in mind, the all-new Horton’s Index will present water-related factoids, touching on the science and the society.

When it comes to conversion of grassland to shrubs or trees, the typical story goes like this. More rainfall is caught be the foliage and evaporated straight back into the air. Higher rates of transpiration deplete soil moisture faster, and deeper roots inhibit drainage of water from soil to aquifer. This story is typical because it is observed time and time again [1], but it is not the whole story. Nor is it always true.

A recent paper in Geophysical Research Letters, by Bradford Wilcox and Yun Huang, tells a different story [2]. They document annual streamflow for several rivers in the Edwards Plateau, central Texas. While the region has experienced an expansion of shrubs and trees – AKA, “woody encroachment” – spring-fed river flow has paradoxically increased.

The reason, they propose, is that while woody plants have expanded, grazing has reduced. Livestock trample and compact the soil, and eat the herbaceous plants, both of which reduce infiltration of water into the soil, and ultimately reducing recharge of the aquifers that feed the springs. But as grazing declined, spring-flow seems to have increased. It thus seems that grazing in the Edwards Plateay has a greater impact of river flow than woody encroachment.

While Wilcox and Huang have started to tell a different story, the story is far from over. They have eliminated historical rainfall as the source of the change, but they have not eliminated historical evaporative demand. And while spring-fed river flow has increased, it seems that flow from other sources has also paradoxically increased. If spring-flow increased due to herbaceous plants favouring infiltration, you’d think surface runoff would drop accordingly, but apparently not.

Whatever the answer, the researchers are on the case, and it is fair to say that another exception to the rule of land use hydrology will be found.

The sudden fall of the Kyrgyz government may have had its roots in meteoric rises in utility rates, including water:

“One expert said the government had triggered the protests by imposing punitive increases on tariffs for water and gas. “In the last few months there has been growing anger over this non-political issue,” said Paul Quinn-Judge, central Asia project director of the International Crisis Group.”

Wondering whether science bloggers have started talking about a meet-up, a google search found the official EGU 2010 conference blog. It’s just got off the ground, offering tips for pending attendees, but I expect it’ll be there live-blogging Kuhn’s the scientific revolution.

“The artesian system shows four or five aquifers, or water-bearing strata, more or less completely separated from one another.”

‘Aquifer’ is a combination of the Latin ‘aqui-’ meaning ‘water’, and ‘-fer’ meaning ‘bearing’ (from the Latin verb ‘ferre’).

‘Ferre’ is also the origin of the English verb ‘to infer’. It was inferred into the English language by 1526 with the meaning ‘to bring into discourse’ or ‘to mention’. By 1529, it had adopted the present connotation, ‘to bring in or draw as a conclusion’.

We’ve all heard the lessons from Easter Island: population growth and a consumer culture butting heads with a finite island. But what teachable moments were there from Easter itself, or from Passover for that matter?

I can see a geology teacher and father taking a frozen Cadbury creme egg, slicing a quarter out of it, and showing his kid the Earth’s structure: chocolate crust, white gooey mantle, and molten caramel core.

To complement the creme egg, common matza come in very handy to the rheological rabbi. Held vertically, their parallel structure depicts the sequential deposits of water and glacial flour.

As for parables, the story of Jesus’ burial on Good Friday and rising on Easter Sunday lends itself well to tale of sedimentary deposit, burial, and subsequent orogenesis, with the newly-risen reaching to the heavens.

And for the 10th plague of Pharaoh’s Egypt, the red of the lamb’s blood illustrates the resilience of iron-containing sedimentary rocks. Banded iron formations are among the oldest known rock formations.

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